Why the study?
Do non-invasive risk stratification techniques identify patients at high risk of arrhythmic death in ischemic heart disease with LVEF < 50%?
Do non-invasive risk stratification techniques identify patients at high risk of arrhythmic death in ischemic heart disease with LVEF < 50%?
In patients with ischemic heart disease, the risk of arrhythmic death is similar regardless of whether LVEF is <30% or ≥30%, and non-invasive risk stratification techniques fail to identify high-risk patients, challenging the current practice of restricting prophylactic ICDs to those with severely reduced LVEF.
Should not yet alter LVEF-based ICD indications in ischemic heart disease; leaves open whether refined non-invasive stratification can identify arrhythmic risk.
BACKGROUND: Risk of arrhythmic death is considered highest in ischemic heart disease with severe left ventricular ejection fraction (LVEF) reduction. Non-invasive testing should improve decision-making of prophylactic defibrillator (ICD) implantation. DESIGN: We enrolled 120 patients with ischemic heart disease and LVEF < 50% and 30 control subjects without ischemic heart disease and normal LVEF. An initial assessment, a second assessment after 3 years and a final follow-up comprised of pharmacological baroreflex testing (BRS), short-term spectral [low-frequency (LF) to high-frequency (HF) ratio] and long-term time-domain analysis of heart rate variability (SDNN), exercise Microvolt T-wave alternans (MTWA) and others. RESULTS: The median follow-up was 7·5 years. Resuscitated cardiac arrest and arrhythmic death due to ventricular arrhythmias ≥ 240/min was observed in 18% and 15% of patients, respectively. Cardiac death was observed in 28% of patients. The incidence of arrhythmic death and resuscitated cardiac arrest was identical in patients with ischemic heart disease with LVEF < 30% and ≥ 30%. No significant difference between subgroups with LVEF of < 30%, 30-39% and ≥ 40% was found either. MTWA, BRS, SDNN and LF to HF ratio failed to identify patients at risk of arrhythmic death in a multiple regression model. CONCLUSIONS: Ischemic heart disease patients with LVEF < 30% and ≥ 30% face the same risk of arrhythmic death. Stratification techniques fail to identify high-risk patients. Therefore, the current practice to constrain prophylactic ICDs to patients with severely reduced LVEF seems to be insufficient.
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Pezawas et al. (2017) studied this question.
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